Vehicles such as an electric vehicle and a hybrid vehicle that are equipped with electric motors (including motors and motor generators in this invention) as drive power sources have been developed. These vehicles generally have a structure in which an electric motor is accommodated in a casing for protecting the electric motor from an external environment or for housing the electric motor integrally with a transmission and thereby sealedly keeping its Automatic Transmission Fluid (ATF). Since an electric power supply of the electric motor is arranged outside the casing, a mechanism is required for electrically connecting this power supply to the electric motor in the casing.
For example, Japanese Patent Laying-Open No. 2004-120961 (Patent Document 1) has disclosed a structure in which a connection unit for electrical connection between an electric motor in a casing and a power cable is spaced in an axial direction (of a rotor rotation axis) from a coil end of the electric motor so that this connection unit can be arranged in a position not restricted by a position of the electric motor coil, and thereby an outer diameter of the structure can be reduced as far as possible.
Japanese Patent Laying-Open No. 2005-229755 (Patent Document 2) has disclosed a structure in which a terminal block for connecting a varnished motor winding to a power cable is arranged on a side surface of an electric motor with respect to a rotor rotation axis direction, and particularly a structure in which a flexible member is arranged on an end of the motor winding so that fixing to the terminal block is performed by canceling tolerances of parts by deformation of the flexible member. Further, Japanese Patent Laying-Open No. 2005-151660 (Patent Document 3) has disclosed a structure for reducing an arrangement space of an electric motor as far as possible. In this structure, a terminal block for connecting a motor winding to a power cable is arranged on a side surface of an electric motor with respect to a rotor rotation axis direction, and is located radially inside an outer peripheral surface of a casing of the electric motor.
Further, U.S. Patent Publication No. 2005/0208782 (Patent Document 4) has disclosed a structure in which a motor generator of a hybrid transmission is connected to an interconnection arranged outside a transmission housing through an opening formed at the housing.
As one of forms of the motor modules, there is a structure including a plurality of electric motors as disclosed in the Patent Document 1. In this structure, for reducing a whole size of motor module, an important matter arises in a connection structure between the electric motor and the external power supply, and more specifically in a manner of arrangement of the connection mechanism between the power cable and a stator coil winding of each electric motor.
Particularly, in the structure having a plurality of electric motors that have the rotation axes in the same direction and neighbor to each other in the rotor rotation axis direction, a plurality of power supplies of the electric motors are generally arranged in one position, and it is necessary to devise a connection mechanism of the power cables that extend from the same side of the plurality of electric motors to the plurality of electric motors.
In connection with this, the Patent Document 1 has disclosed the foregoing connection mechanism in which the terminal blocks of the two electric motors are spaced from the coil ends. However, this structure increases a length of the motor module in the rotor rotation axis direction, and may impair mountability. Since the two electric motors are accommodated in the same casing, assembly operations for the respective electric motors cannot be performed in parallel without difficulty. This may cause complication of the assembly operations as well as increase in time required for them, and thus may deteriorate productivity. In Patent Documents 2 and 3, no consideration is given to the structure that has the plurality of electric motors neighboring to each other.
Further, if the connection structure for the power cable and the electric motor has an opening in the housing or casing as disclosed in the Patent Document 4, this may cause disadvantages such as increase in number of parts for a sealing structure and oil leakage due to insufficient sealing property.